Modern wind turbine rotor blades are built from fiber-reinforced plastics. A rotor blade typically includes an airfoil having a rounded leading edge and a sharp trailing edge. The rotor blade is connected with its blade root to a hub of the wind turbine. The blade root includes a plurality of root bushings. The root bushings can be provided with an internal thread. Bolts are engaged with theses threads to connect the blade root to the hub. EP 1 486 415 A1 describes such a root bushing. A connection between the root bushing and a pitch bearing of the hub is a friction connection. The quality of this connection is dependent on the contact area between the root bushing and the pitch bearing.